Participants in the 2008 FHI Global Catastrophic Risk conference estimated a probability of extinction from nano-technology at 5.5% (weapons + accident) and non-nuclear wars at 3% (all wars - nuclear wars) (the values are on the GCR wikipedia page). In the Precipice, Ord estimated the existential risk of Other anthropogenic risks (noted in the text as including but not limited to nano-technology, and I interpret this as including non-nuclear wars) as 2% (1 in 50). (Note that by definition, extinction risk is a sub-set of existential risk.)
Since starting to engage with EA in 2018 I have seen very little discussion about nano-technology or non-nuclear warfare as existential risks, yet it seems that in 2008 these were considered risks on-par with top longtermist cause areas today (nanotechnology weapons and AGI extinction risks were both estimated at 5%). I realize that Ord's risk estimates are his own while the 2008 data is from a survey, but I assume that his views broadly represent those of his colleagues at FHI and others the GCR community.
My open question is: what new information or discussion over the last decade lead the GCR to reduce their estimate of the risks posed by (primarily) nano-technology and also conventional warfare?
At the start of Chapter 6 in the precipice, Ord writes:
This made me recall hearing about Matsés, a language spoken by an indigenous tribe in the Peruvian Amazon, that has the (apparently) unusual feature of using verb conjugations to indicate the certainty of information being provided in a sentence. From an article on Nautilus:
I doubt the Matsés spend much time talking about existential risk, but their language could provide an interesting example of how to more effectively convey aspects of certainty, probability and evidence in natural language.
According to Fleck's thesis, Matsés has nine past tense conjugations, each of which express the source of information (direct experience, inference, or conjecture) as well as how far in the past it was (recent past, distant past, or remote past). Hearsay and history/mythology are also marked in a distinctive way. For expressing certainty, Matsés has a particle ada/-da and a verb suffix -chit which mean something like "perhaps" and another particle, ba, that means something like "I doubt that..." Unfortunately for us, this doesn't seem more expressive than what English speakers typically say. I've only read a small fraction of Fleck's 1279-page thesis so it's possible that I missed something. I wrote a lengthier description of the evidential and epistemic modality system in Matsés at https://forum.effectivealtruism.org/posts/MYCbguxHAZkNGtG2B/matses-are-languages-providing-epistemic-certainty-of?commentId=yYtEWoHQEFuWCehWt.